Soft robotic actuator attachment hub and grasper assembly, reinforced actuators, and electroadhesive actuators

ABSTRACT

A hub assembly for coupling different grasper assemblies including a soft actuator in various configurations to a mechanical robotic components are described. Further described are soft actuators having various reinforcement. Further described are and soft actuators having electroadhesive pads for improved grip, and/or embedded electromagnets for interacting with complementary surfaces on the object being gripped. Still further described are soft actuators having reinforcement mechanisms for reducing or eliminating bowing in a strain limiting layer, or for reinforcing accordion troughs in the soft actuator body.

RELATED APPLICATIONS

The present application claims priority to U.S. Patent Application Ser.Nos. 62/051,546 and 62/051,571, both filed on Sep. 17, 2015. Thecontents of the aforementioned applications are incorporated herein byreference. Moreover, various soft robotic technologies are discussed inPCT International Publication Number WO2012/148472, which application isincorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The disclosure relates generally to the field of robotics andparticularly to hubs and assemblies for interfacing soft roboticactuators with another mechanical system and to reinforced and/orelectromagnetically augmented soft actuators.

BACKGROUND

Robotics are used in many industries, such as manufacturing, industrialapplications, medical applications, and the like. Soft robotics is adeveloping area of robotics that provides soft, conformal, and adaptivegraspers and actuators to enable robots to interact with objects in asimilar manner to a human. In particular, such robots are able tomanipulate objects in the same manner as a human hand. For example, if apart is on a shelf, a moving belt, or being moved from a shelf to abelt, an end effector may adapt to picking up the object from variousdirections, such as a “side pick” or a “top down pick.” This samegrasper may also adapt to varying objects in each task, just as thehuman hand can.

A magnetic assembly to combine “hard” and “soft” robotics has beendisclosed in A Hybrid Combining Hard and Soft Robotics, Stokes Adam A.,Shepherd Robert F., Morin Stephen A., Ilievski Filip, and WhitesidesGeorge M., Soft Robotics. March 2014, 1(1): 70-74.doi:10.1089/soro.2013.0002, which article is incorporated herein byreference in its entirety. However, the proposed combination of hard andsoft robotics does not provide the versatility necessary to operatesimilar to a human.

In particular, current end effectors have difficulty adapting to varyingpart location (e.g., on a shelf, on a conveyor belt, or the like).Additionally, current end effectors have difficulty adapting to varyingpart sizes and geometries. Still further, current end effectors needcomplex control systems to operate.

Furthermore, conventional soft robotic actuators are constructed from asingle elastomeric material such as silicone elastomer. Some actuatorsincorporate elastomers of differing stiffness or wall thickness toaccommodate a certain desired behavior. This layer of varying thicknessor stiffness is sometimes referred to as a strain limiting layer. Someactuators use incorporated or coextruded fibrous materials in theelastomer body of the actuator itself. Such co-molded fibers areintended to improve resistance to puncture and strengthen the actuator.Some actuators use textile socks with slits to increase the operatingpressure regime of an actuator.

However, all of these actuators have several limitations. In particular,actuators that use similar but stiffer elastomers to reinforce orrestrain the actuator with thinned or thickened wall sections quicklybecome heavy and bulky because of the amount of excess material neededto achieve desired behaviors. This is because while stiffer, bothmaterials are still elastomers of similar chemistries and can onlyachieve a very limited stiffness differential. In the case of silicones,whose stiffness is highly correlated with hardness, useful materials forsoft actuators typically fall within the range of 10-80A Durometeryielding at most an 800% differential in stiffness between selectregions of the actuator. This also means that when higher differentialsin stiffness are achieved, it is mostly at the expense of strength inthe weaker and softer elastomer regions.

Similarly, actuators that achieve higher function through reinforcementvia thickened walls or slightly stiffer variants of elastomer are alsolimited to a select set of other equally important mechanicalproperties. As a result, these actuators can have poor mechanicaldamping characteristics, causing the actuator to appear floppy or poorlycontrolled. Additionally, such actuators can have limited resistance totear or ablation compared to materials better suited to withstandpuncture, acute damage, thermal shock, or general wear and fatigue.Furthermore, the load response of these construction materials is almostuniversally isotropic.

Actuators with fibrous reinforcements have been introduced by moldingfibers into the actuator or co-extruded fibrous “pulp” as filler.Although such techniques provide slight improvements in punctureresistance and increased overall strength, this type of actuatorprecludes the possibility of modularity or repairs to suchreinforcements without discarding the entire actuator. Additionally,fibrous reinforced actuators present a vulnerable rubbery surface to theenvironment, and issues of fiber delamination from the elastomer,limited fatigue life, and poor environmental resistance are prevalent.

The present disclosure is directed to the above limitations. Inparticular, the present disclosure provides improvements in interfacinghard and soft robotics and also provides improved actuators.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an exemplary embodiment of ahub assembly and soft robotic actuators in accordance with variousexamples of the present disclosure.

FIGS. 2A-2C are exploded views of the hub assembly of FIG. 1.

FIGS. 3A-3E are assembled views of the hub assembly and soft roboticactuators of FIG. 1.

FIGS. 4A-4D are perspective views illustrating an exemplary twist lockinterface for the hub assembly of FIG. 1.

FIG. 5 is an illustration of a method of using the twist lock interfaceof FIGS. 4A-4D.

FIG. 6 is a cross sectional view of the twist lock interface of FIGS.4A-4D.

FIGS. 7A-7G are perspective views illustrating an exemplary magneticinterface for the hub assembly of FIG. 1.

FIG. 8 is a perspective view illustrating an exemplary electrostaticadhesion interface for the hub assembly of FIG. 1.

FIGS. 9A-9D are perspective views illustrating an example grasper usingthe hub assembly of FIG. 1 and soft actuators.

FIGS. 10A-10C are perspective views illustrating an example grasperusing the hub assembly of FIG. 1 and soft actuators having electromechanical portions.

FIGS. 11A-11E are perspective views illustrating a grasper using the hubassembly of FIG. 1 and soft actuators having side actuators configuredto change the angle of attack.

FIGS. 12A-12D are perspective views illustrating a grasper using the hubassembly of FIG. 1 and soft actuators of different lengths configured tosubstantially enclose an object.

FIG. 13 is an illustration of a method of using the grasper of FIGS.12A-12D.

FIGS. 14-21 are perspective views of reinforced actuators.

FIGS. 22-26 are perspective views of reinforcing wraps for use with asoft actuator.

FIGS. 27-28 depict an exemplary soft actuator having embeddedelectromagnets properties

FIGS. 29A-29C depict exemplary electroadhesive structures suitable forembedding in a soft actuator.

FIGS. 30A-30F depict exemplary reinforcement structures for reinforcinga soft actuator.

SUMMARY

“Soft robotic” actuators that are configured to perform new fundamentalmotions (e.g., bending, twisting, straightening, or the like) aredescribed. Additionally, a hub and grasper assembly for such softrobotics actuators is described. Exemplary embodiments may employ softrobotic technologies in specific configurations that are useful asorthopedic devices, and related methods that employ such soft roboticconfigurations.

Some embodiments of the present disclosure describe a hub assemblycapable of interfacing with various soft robotics actuators (e.g.,Pneu-Net actuators, fiber reinforced actuators, soft tentacle actuators,accordion style actuators, or the like) and hard robotics (e.g., roboticarms, mechanical tools, or other mechanical systems).

Additionally, some embodiments of the present disclosure provide agrasper including elastomeric actuators. The grasper is conformal andadaptive to enable the handling of a range of items, with real-timeadaption to the shape and size of the object.

Additionally, some embodiments of the present disclosure provide areinforced actuator. In particular, an actuator with various geometries(e.g., unfolding accordion style actuator, or the like) and reinforcedareas is provided. In some embodiments, soft actuators havingreinforcement mechanisms for reducing or eliminating bowing in a strainlimiting layer are provided.

According to some embodiments, the elastomeric or reinforced actuatorsmay be provided with one or more embedded magnetic surfaces orelectroadhesive pads. The magnetic surfaces may be configured tointerface with a complementary surface on a gripped substrate. Regardingthe electroadhesive pads, when placed in proximity to a substrate,electrostatic forces are created between the substrate and theelectroadhesive pads. This allows for improved adhesion between theactuator and the material being gripped, where the adhesion can bereadily activated or deactivated.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. The invention, however, may be embodied inmany different forms and should not be construed as being limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. In thedrawings, like numbers refer to like elements throughout.

In accordance with the present disclosure, a hub and/or grasper assemblyfor interfacing soft robotic actuators with hard robotic assemblies isprovided. Additionally, reinforced actuators are described. Thereinforced actuators may be used with the hub and/or grasper assembly.However, for purposes of convenience, they are discussed separately. Inparticular, FIGS. 1-13 depict examples of a hub or grasper assemblyaccording to embodiments of the present disclosure while FIGS. 14-27Cdepict examples of actuators according to embodiments of the presentdisclosure.

Referring to FIG. 1, an exemplary hub 100 in accordance with the presentdisclosure is shown. The hub 100 includes a master side assembly 10 anda tool side assembly 20. In general, the master side assembly 10 may beconnected or connectable to a mechanical assembly, such as a roboticarm, a robotic manipulator, or in general any end effector of a robotic(e.g., hard robotics) assembly. The tool side assembly 20 may beconfigured to operably connect various soft actuators 30-a (where a is apositive integer). In particular, the tool side assembly 20 may beprovided with actuator attachment portions 20-b (where be is a positivenumber). It is important to note, that the tools side assembly 20 may beconfigured connect any number of soft actuators 30-a. However, forconvenience and clarity, a number of soft actuators 30-a (e.g., 30-1,30-2, 30-3, and 30-4) and a number of actuator attachment portions 20-a(e.g., 20-1, 20-2, 20-3, and 20-4) are depicted in the figures.Additionally, it is important to note that the number of actuatorattachment portions 20-b may be different than the number of actuators30-a connected to the tool side assembly 20.

In general, each of the master side assembly 10 and the tool sideassembly 20 include an interface configured to releaseably couple theassemblies 10 and 20 to each other. In particular, the tool sideassembly 20 includes an interface portion 21 while the master sideassembly includes an interface portion 11 (obscured by the angle ofviewing). The interface portions 11 and 21 can be configured to couplethe assemblies 10 and 20 and to provide a seal for inflation line (e.g.,pneumatic, hydraulic, or the like) connections, electrical connections,or other connections.

FIGS. 2A-2C depict an exploded view of the hub 100 from variousperspectives. In particular, FIG. 2A illustrates the hub 100 from astraight on side view showing the master side assembly 10 and the toolside assembly 20. Furthermore, actuator attachment portion 22-1 is shownin the tool side assembly 20. Additionally, the interface portions 11and 21 are shown. FIG. 2B illustrates the hub 100 from an angled bottomup perspective view showing the master side assembly 10 and the toolside assembly 20. Furthermore, actuator attachment portion 22-1 and 22-2are shown in the tool side assembly 20. FIG. 2B illustrates the hub 100from an angled bottom up perspective view showing the master sideassembly 10 and the tool side assembly 20. Furthermore, actuatorattachment portion 22-1 and 22-2 are shown in the tool side assembly 20.Additionally, the interface portions 11 and 21 are shown. FIG. 2Cillustrates the hub 100 from an angled top down perspective view showingthe master side assembly 10 and the tool side assembly 20. Furthermore,actuator attachment portion 22-1 and 22-2 are shown in the tool sideassembly 20. Additionally, the interface portions 11 and 21 are shown.

It is to be appreciated, that areas of the interface portions 11 and 21are merely depicted in FIG. 1 and FIGS. 2A-2C. However, it is to beappreciated, that the interface portions may have a variety ofconfigurations and the interface portion should not be limited by thatdepicted in FIG. 1 and FIGS. 2A-2C.

FIGS. 3A-3E depict an assembled view of the hub 100 and attachedactuators 30 from various perspectives. In particular, FIG. 3Aillustrates the hub 100 from a straight on side view showing the masterside assembly 10 and the tool side assembly 20. Furthermore, actuators30-2 and 30-3 are shown attached to the tool side assembly 20. Actuators30-2 and 30-3 are depicted in a “neutral” position (e.g., not inflated,deflated, or the like). FIG. 3B illustrates the hub 100 from a straighton side view showing the master side assembly 10 and the tool sideassembly 20 and the attached actuators 30-2 and 30-3 in an inflatedstate. FIG. 3C illustrates the hub 100 from an angled side view whileFIGS. 3D and 3E show the hub 100 from an angled bottom up and tom down(respectively) perspective view. In particular, the assemblies 10 and 20are shown coupled together with actuators 30-1, 30-2, 30-3, and 30-4attached to the tool side assembly and depicted as inflated.

Accordingly, the hub assembly 100 can be used to quickly switch betweenvarious grasper assemblies by changing the tool side assembly 20.Example grasper assemblies are now described. It is important to note,that a system may be implemented with one master side assembly 10 andmultiple the tool side assemblies 20 each with a different grasperconfiguration. As such, the system can be quickly reconfigured and usedto perform different operations needing different graspers or softactuators.

FIGS. 4A-4D depict an example of the hub assembly 100 including a twistlock interface. In particular, FIG. 4A illustrates an exploded top downperspective view of the hub assembly 100 showing the master sideassembly 10 and the tool side assembly 20. Furthermore, actuatorattachment portions (e.g., 22-1) are shown in the tool side assembly 20.Furthermore, details of the interface portions 11 and 21 are shown. Inparticular, the interface portion 11 includes pegs 15 and connectionport 16 while the interface portion 21 includes slots 25 and connectionport 26. The pegs and the slots are configured to be releaseably securedto each other. In particular, the slots 25 may have a varying diameter,where one end of each slot is proportioned to receive an end of acorresponding one of the pegs 15. Once the pegs 15 are fit into theslots 25, either the assembly 10 or the assembly 20 may be twisted tolock the pegs 15 in place, thereby securing the assembly 10 to theassembly 20.

FIGS. 4B-4C illustrate a top perspective and a top down (respectively)view of the tool side assembly 20. As can be seen, the tool sideassembly 20 includes actuator attachment portions (e.g., 20-1), slots25, and connection port 26. FIG. 4D illustrates a side view of the toolside assembly 20. As can be seen, the tool side assembly 20 may includea top stepped or recessed portion 22 configured to fit into acorresponding recessed portion in the interface portion 11 of the masterside assembly 10.

Additionally, the connection ports 16 and 26 may seal or form a sealwhen the assemblies 10 and 20 are secured together (e.g., refer to FIG.6). As such, a sealed pathway or connection point for inflation lines(e.g., pneumatic, hydraulic, or the like) as well as electrical signallines can be provided through the connection points 16 and 26.

FIG. 5 illustrates a method for securing the tool side assembly 20 tothe master side assembly 10. In particular, at 510, the interfaceportion 11 of the master side assembly 10 is lowered (or dropped) ontothe interface portion 21 of the tool side assembly 20. In particular,the interface portions 11 and 21 are brought together such that the pegs15 fit into the slots 25. It is important to note, that this figuredepicts pegs disposed on the tool side assembly and slots on the masterside assembly. Examples are not to be limited in this context. At 520,the master side assembly 10 is twisted relative to the tool sideassembly 20 to lock the pegs 15 into the slots 25. Accordingly, at 530,the tool side assembly 20 is securely coupled to the master sideassembly 10.

FIG. 6 illustrates a cross sectional view of the assembled hub 100. Inparticular, as depicted, the pegs 15 are secured into slots 25 and theconnection points 16 and 26 form a sealed connection.

FIGS. 7A-7G depict an example of the hub assembly 100 including amagnetic interface. In particular, FIG. 7A illustrates an explodedbottom up perspective view of the hub assembly 100 showing the masterside assembly 10 and the tool side assembly 20. Furthermore, actuatorattachment portions (e.g., 22-1) are shown in the tool side assembly 20.Furthermore, details of the interface portions 11 and 21 are shown. Inparticular, the interface portion 11 includes connection ports 16 and26, respectively. Furthermore, the interface portion 11 includes ageometric (e.g., hexagonal, triangular, rectangular, star shaped, or thelike) recess 13 while the interface 21 includes a correspondinggeometric stepped portion 23. The stepped portion 23 is configured tofit into the recessed portion 13. Furthermore, the interfaces 10 and 20include magnetic portions 41 and 42, respectively. The geometric steppedportion 23 and the recessed portion 13 are configured to prevent anyshear forces from disengaging the tool side assembly 20 from the masterside assembly 10. Furthermore the stepped portion 23 and the recessedportion 13 facilitate the location and insertion of the tool sideassembly 10.

FIGS. 7B-7C illustrate the hub assembly 100 in an alternativeperspective view and a side view, respectively. Additionally, FIGS.7D-7G illustrate the tool side assembly from various angles and/orviews.

FIG. 8 depicts an example of the hub assembly 100 including anelectrostatic adhesion interface. In particular, this figure illustratesan exploded bottom up perspective view of the hub assembly 100 showingthe master side assembly 10 and the tool side assembly 20. Furthermore,actuator attachment portions (e.g., 22-1) are shown in the tool sideassembly 20. Furthermore, details of the interface portions 11 areshown. In particular, the interface portion 11 includes electrostaticadhesion pads 51. As depicted, the electrostatic adhesion pads aredisposed on the master side assembly 10. However, in some examples, theelectrostatic adhesion pads 51 can be disposed on the tool side assembly20. Furthermore, in some examples, electrostatic adhesion pads (e.g.,51) may be disposed on both the master side assembly and the tool sideassembly interface portions 11 and 21. In still further embodiments, oneor more electrostatic adhesion pads may be embedded in the body of thesoft actuator, at various points along the gripping surface of theactuator. The electrostatic adhesion pads may augment the grippingstrength of the actuator. Exemplary electrostatic adhesion pads arediscussed in connection with FIGS. 29A-29C.

FIGS. 9A-9D illustrate an example hub assembly 100 and an exampleconfiguration of soft actuators 30 attached to the tool side assembly20. In particular, the soft actuators 30 are depicted in FIGS. 9A-9C asdeflated to vacuum (e.g., reverse inflated) to provide an increase ingrasping fidelity. In some examples, the connection ports 16, 26 mayprovide for sealing inflation lines between the assemblies 10 and 20such that the soft actuators 30 can be deflated and/or inflated. In someexamples, the soft actuators 30 may be inflated from the deflatedportion, resulting in inflated actuators 30, as shown in FIG. 9D.

FIGS. 10A-10C illustrate an example hub assembly 100 and an exampleconfiguration of soft actuators 30, that include an electro-mechanicalportion 31. The electromechanical portions 31 can be used to modifyand/or adjust the angle of attack of the actuators from when they are inthe neutral position (e.g., refer to FIGS. 10A-10B) to when they are inthe inflated position (e.g., refer to FIG. 10C).

FIGS. 11A-11E depict an example of the tool side assembly 20 andattached soft actuators 30. In some examples, a tool side assembly 20may be provided with the soft actuators depicted in this example toadjust the angle of attack for picking up object. For example, FIG. 11Aillustrates the tool side assembly 20 and the soft actuators 30 fromvarious angles and perspectives. As depicted, the soft actuators 30include soft angle adjustors 32. FIG. 11B illustrates a bottom view ofthe tool side assembly 20 with the soft actuators 30 attached and amagnified view 200 of the soft angle adjustors 32. As can be seen, thesoft angle adjustors 32 are disposed laterally between the softactuators 30. During operation, the soft angle adjustors 32 can beindependently inflated and deflated (e.g., independent from each other,independent from the soft actuators, some combination of this, or thelike) to adjust the angle between the soft actuators 30.

FIG. 11C-11E illustrate the soft actuators 30 and soft angle adjustors32 in various states. In particular, FIG. 11C illustrates the softactuators 30 in a neutral position and the soft angle adjustors 32deflated. As such, the angle between pairs of the soft actuators 30(e.g., between 30-1 and 30-2 and between 30-3 and 30-4, or the like) isreduced. FIG. 11D illustrates the soft actuators 30 in a neutralposition and the soft angle adjustors 32 inflated. As such, the anglebetween pairs of the soft actuators 30 (e.g., between 30-1 and 30-2 andbetween 30-3 and 30-4, or the like) is increased. FIG. 11E illustratesthe soft actuators 30 in an inflated position and the soft angleadjustors 32 inflated. As such, the angle between pairs of the softactuators 30 (e.g., between 30-1 and 30-2 and between 30-3 and 30-4, orthe like) is increased and the angle of attack of the inflated softactuators 30 is also increased.

FIGS. 12A-12D depicts an example of the tool side assembly 20 andattached soft actuators 30. In some examples, a tool side assembly 20may be provided with the soft actuators depicted in this example (e.g.,soft actuators of varying sizes) to enable the soft actuators to fullyencapsulate and object. For example, FIG. 12A illustrates the tool sideassembly 20 and the soft actuators 30 from various angles andperspectives. As depicted, there are a variety of different sized softactuators 30. In particular, the soft actuators 30 depicted have variouslengths. FIGS. 12B-12D illustrate the tool side assembly 20 and each ofthe different sized the soft actuator 30 and their corresponding rangeof motion. In particular, FIG. 12B illustrates the longest of the softactuators 30 and their corresponding range of motion (e.g., deflated tofully inflated). FIG. 12C illustrates the middle length soft actuators30 and their corresponding range of motion (e.g., deflated to fullyinflated). FIG. 12D illustrates the shortest of the soft actuators 30and their corresponding range of motion (e.g., deflated to fullyinflated).

FIG. 13 illustrates a method of fully encapsulating an object using anexample tool side apparatus and soft actuators arranged according to thepresent disclosure. In particular, at 1310, the tool side assembly andsoft actuators are arranged above an object 1301 to be encapsulated(e.g., mug, or the like). As 1320, the tool side assembly and the softactuators are lowered or positioned just above the object. At 1330, theshortest soft actuators 30 are inflated to hold the object in place. At1340, the middle length soft actuators are inflated to more fullysurround the object 1301. As 1350, the longest soft actuators areinflated to substantially encapsulate the object 1301.

FIG. 14 depicts an embodiment of a reinforced actuator 1400 that uses areinforcing wrap 1401 that can be fabricated in a flat sheet and thensubsequently affixed about an actuator 1402 by mating its ends in one ofa variety of different methods. This reinforcing wrap 1401 may befabricated through any method suitable for such a shape and is notnecessarily limited to being completely flat. For instance it may beformed to achieve texture for gripping, ridges for stiffness, orunfolding features to accommodate extension. The material from which thereinforcing warp 1401 is made may vary greatly depending on the intendedapplication. For example, without limitations, the wrap 1401 can befabricated from metal meshes or fabrics, polypropylene, polyester,polyethylene, lubricant impregnated polymers, mylar, spandex, neoprene,nitrile, latex, textiles, elastomeric textiles, sealable or film coatedtextiles, elastomers, thermoplastic films or sheets, thermoplasticelastomer films or sheets, nonwoven textiles, paper or other cellulosicmaterials, uniaxially oriented textiles, fibrous composites, foams,thermoplastic foams, thermoplastic elastomer foams, thermally andelectrically conductive materials, strain sensitive materials, flexibleelectronic substrates such as polyamide, and others. In addition, thereinforcing wrap 1401 may also include less flexible stiffening elementsdesigned to provide completely rigid regions or tunably stiff regions.Such materials may include, for example, nitinol hyper-elastic springs,spring steel, metal plates, helical springs, plastic or thermoplasticplates, traditional printed circuit boards, and others.

FIG. 15 depicts a reinforced actuator 1500 including a reinforcing wrap1501 that can be constructed from woven materials, such as, for example,a co-weave of elastomeric strands such as neoprene or spandex. The wrap1501 has the unique ability to apply tension and conform about thesurface of the actuator 1502 it is reinforcing. By default a specificamount of expansion will be resisted by the elasticity of the fabric upto some point where the mesh angle of fabric collapses and it begins torespond as a rigid fibrous mesh.

FIG. 16 depicts a reinforced actuator 1600 having internalreinforcements 1601 molded within the body of the actuator 1602. Such aconfiguration may reinforce the actuator 1600 against undesirableexpansion.

FIG. 17 depicts a reinforced actuator 17000 including an externalreinforcement 1701. The external reinforcement 1701 may be a tunablystiff element configured to change the resistance of the actuator 1702to unfolding and extending under pressure. For example, the externalreinforcement 1701 may be a member that is rigid along the straightsides of the accordion geometry (depicted as checkered) and“spring-like” in the curved regions between (depicted as white) augmentsthe normal response of the accordion actuator to pressure andeffectively raises its operating pressure regime. This leads to a partwhich is substantially stiffer in the curved state and which is capableof exerting greater forces on its environment.

FIG. 18 depicts a reinforced actuator 1800 including dampeningreinforcements 1801 disposed inside the actuator 1802. The actuator 1800may be implemented in systems where closed loop control is to be appliedor in applications where a high level human interaction dictates theappearance of precise control. In such systems it is often desirable todampen oscillations within the system. For example, it may beadvantageous to reject oscillations introduced by external stimuli andcontrol the actuator 1800 in a frequency band far from its mechanicalnatural resonance frequency. To this effect, the dampeningreinforcements 1801 may be highly damping viscoelastic foams or gelsthat fill the interior of the actuator 1802 in an open celledconfiguration. An inflation channel 1803 is left open in this depictionto ensure all areas of the actuator inflate at the same time. If thematerial comprising the dampening reinforcement 1801 is mechanicallyrobust as well as highly damping, it can also serve as a volumousinternal reinforcement against undesired expansion of the part.

FIG. 19 depicts a reinforced actuator 1900 where a dampeningreinforcement 1901 (e.g., similar to that dampening reinforcement 1801)is disposed on the exterior of the actuator 1902. This amplifies theirdamping effect, as this region of the part must stretch the most for theactuator 1902 to bend.

FIG. 20 depicts a reinforced actuator 2000 that including an externalreinforcement 2001 and an actuator 2002. The external reinforcement 2001may have any of a variety of configurations and features, even complexconfigurations and features. Such complex external reinforcementfeatures may be achieved using additive manufacturing techniques. Insuch techniques, a material that is sensitive to a particular wavelengthor spectrum is applied uncured to a surface upon which it issubsequently cured via exposure to radiation. In particular, the use ofmicro dispensed fluids also enables the deposition of a controlledmixture of multiple compounds across a surface, effectively setting upmicro-scale reactions on the surface that can spatially modulate theproperties of the cured material. Such techniques may be employed toform the complex reinforcement 2001 shown on the surface of a softactuator 2002. Additionally, these techniques may be employed on thesurface of soft actuators to selectively add patterned layers ofmaterial with a wide range of properties. They may be stiffreinforcements, elastomeric textures, aesthetic patterns, opticalelements, protective layers, conductive layers, or strain sensitiveresistive materials

FIG. 21 depicts a reinforced actuator 2100 comprising a soft actuator2102 and a protective skin 2101 drawn over the soft actuator 2102. Thinand wrinkled or highly elastomeric skin materials can be used for amultitude of different applications including protection of theactuator, containers for filler materials (not shown) that surround theactuator, high or low friction, chemical resistance, or the like.

FIGS. 22-26 depict examples of reinforcing wraps (e.g., the wrap 1401,1501, or the like) that may be implemented with various examples of thepresent disclosure. The wraps 1401 and 1501 discussed above may beformed as described below. Turning to FIG. 22, a reinforcing wrap 2200is depicted. The wrap 2200 can be permanently or reversibly affixedabout an unfolding accordion soft actuator. The wrap 2200 can be formedusing laser cutting, knife cutter plotting, sewing, impulse sealing, RFwelding, ultrasonic welding, hot embossing, compression molding, orinjection molding. Additionally, the wrap 2200 may include side releasebuckles 2201 to be affixed about a soft actuator. The wrap 2200 can alsohouses a number of sensors 2202 and/or electrical payloads 2203 that maybe disposed on and/or embedded within the wrap 2200. For example, asdepicted, the electrical payload 2203 includes a traditional printedcircuit board with microcontroller based application circuit, batterypower and distribution, and a suite of myoelectric sensors 2202 designedto detect the muscle intent of the biological subject they are incontact with.

Turning now to FIG. 23, a reinforcing wrap 2300 is depicted. The wrap2300 may include any combination of features described above forreinforcing wraps. Additionally, the wrap 2300 includes re-closableinterlocking pegs 2301 as a fastener and force sensing resistors orpressure transducers 2302 sensed via conductive threads 2303 embeddedwithin the wrap material.

Turning now to FIG. 24, a reinforcing wrap 2400 is depicted. The wrap2400 may include any combination of features described above forreinforcing wraps. Additionally, the wrap 2400 includes strain sensingmaterials 2401 spanning the reinforcements that connect the two halvesof the wrap's structure.

Turning now to FIG. 25, a reinforcing wrap 2500 is depicted. The wrap2500 may include any combination of features described above forreinforcing wraps. Additionally, the wrap 2500 includes strips ofadhesive 2501 as a fastener and a bank of light emitting diodes 2502powered externally via wires 2503 embedded within the wrap.

Turning now to FIG. 26, a reinforcing wrap 2600 is depicted. The wrap2600 may include any combination of features described above forreinforcing wraps. Additionally, the wrap 2600 includes protective armorplates 2601 embedded within its bottom facing surface and a tunednitinol or spring steel accordion spring 2602 to provide additionalresistance to unfolding and elongation of the contained actuator.

FIG. 27 and FIG. 28 depict examples of actuators having embeddedelectromagnets 2701, 2801 for allowing the actuators to interface withan object being gripped, for example through induction coils in theelectromagnet or located on the surface of the object.

The embodiment depicted in FIG. 27 includes a single electromagnet 2701embedded in the base of the hub 2702, where the hub 2702 attaches to theactuators 2703 and orients the actuators 2703. This allows theelectromagnet 2701 to interact with a complementary surface on the topof the gripped object, facing towards the direction of the hub 2702, asshown by the arrow 2704. Two additional electromagnets 2701 areincluded, one at the end of each actuator 2703. This allows theelectromagnets 2701 to interface with complementary surfaces facing inthe directions indicated by the arrows 2705.

The embodiment depicted in FIG. 28 includes three electromagnets 2801.Although the depicted embodiment includes three electromagnets 2801embedded in the side of the actuator 2803, exemplary embodiments mayemploy one or more electromagnets 2801. For reference, exemplaryelectromagnetic field lines 2802 are shown in relation to the bottomelectromagnet 2801.

The electromagnets 2801 may be rigid, flexible, or elastomeric and maybe embedded within the material of the actuator 2803. The location ofelectromagnetic elements within the actuator 2803 may be selected suchthat complementary textures or surface properties are present on eitherthe actuator or the object being gripped (e.g., ferromagnetic material,roughened surfaces, pressure sensitive adhesive, suction cups, etc.), oras a means of interacting with an object that has electrical subsystems.For instance, if the object which is gripped has a correspondinginducting coil, the activation of the electroadhesive pads 2801 withinthe actuator 2803 may be used to induce electrical current in thegripped object for purposes of providing power or communicating.

FIGS. 29A-29C depict exemplary electroadhesive pads suitable for usewith exemplary embodiments described herein. Electroadhesion is anelectrically controlled, astrictive adhesion technology used inapplications such as gripping that often require reversible,adhesive-free binding to a substrate. Electroadhesion works by creatingelectrostatic forces between an electroadhesive pad and a substrate thatis either electrically insulating or conductive.

Augmenting the grip strength may be accomplished by actuating theelectroadhesive pad(s) to attract (pull) a gripped object at selectlocations, repel (push) the gripped object at select locations, or toselectively attract and repel the object at different points. Theelectroadhesive pads may either improve or intentionally loosen the gripon the object by the actuator(s).

As shown in FIG. 29A, an exemplary electroadhesive pad may include twointerdigitated electrodes patterned on the surface of a dielectricmaterial. The pad may be fabricated as a flexible or stretchableelectronic using a variety of methods, such as inkjet printing, stencilprinting, lithographic patterning of thermally evaporated metals,lithographic patterning of sputter coated metals, or laser sintering ofmetal particles.

FIG. 29B depicts an example of such an electroadhesive pad embedded in asoft actuator. As described above, the soft actuator may have anextensible pneumatic layer and a less extensible layer. In theembodiment of FIG. 29B, the electroadhesive pad is embedded in the lessextensible layer of the actuator.

FIG. 29C shows what occurs when the interdigitated electrode is charged.Fringe field lines are created between the positive and negativeelectrodes that extend in the direction normal to the electrode pattern.When the electroadhesive pad is brought in proximity to a substrate(e.g., glass, drywall, wood, concrete, metals, etc.), its fringe fieldlines penetrate the substrate and redistribute charge to create apattern of opposite polarity in the substrate. The coulombic attractionbetween the charges on the electrode and the complementary, inducedcharges on the surface of the substrate creates an electrostatic forcethat can be used to adhere the electroadhesive pad to the substrate.Controlling of the electrostatic adhesion voltage permits the adhesionto be turned on and off easily.

Turning next to FIGS. 30A-30F, reinforced actuators for preventingbowing in a strain limiting layer are now described. The strain limitinglayer of a soft actuator can have the tendency to bow away from theneutral bending plane of the actuator during inflation. This bowing ofthe strain limiting layer increases the second moment of area of theactuators cross section thereby increasing the actuators resistance tobending. This behavior diminishes the function of the actuator.

This problem can be mitigated by overmolding rigid elements (e.g.plastics, metals, ceramics, or stiffer elastomers) in to the strainlimiting layer. This is accomplished by placing a plurality of rigidelements into the strain limiting layer where the long axis of eachelement is oriented perpendicular to the neutral axis of bending. Thisorientation allows the rigid elements to prevent bowing of the strainlimiting layer in the direction perpendicular to the neutral axis butonly minimally impedes bending along the neutral axis.

The rigid elements may be held in place between the strain limitinglayer of the soft actuator body and an overmolded encapsulatingelastomer layer. FIG. 30A depicts side-by-side bottom views of a softactuator body 3001 without an encapsulating elastomer layer on thestrain limiting layer 3002 (left), and the same soft actuator bodyhaving an encapsulating elastomer layer 3003 (right). The encapsulatingelastomer layer 3003 may be made of the same materials as the softactuator body (e.g., the same elastomer materials), or may be made of arelatively more rigid material. FIG. 30B are side-by-side side views ofthe soft actuator body 3001 with and without the encapsulating elastomerlayer 3003 on the strain limiting layer 3002 (top and bottom,respectively).

In some embodiments, the encapsulating elastomer layer 3003 may overlayreinforcing slats 3004 in order to prevent bowing in the strain limitinglayer 3002. The soft actuator body 3001 may be provided with moldedtrenches 3005 for receiving the reinforcing slats 3004. Alternatively orin addition, the molded trenches 3005 may be located in theencapsulating elastomer layer 3003, or trenches 3005 may be located bothin the soft actuator body 3001 and the encapsulating elastomer layer3003. In assembly, the reinforcing slats may be slotted into thetrenches 3005 and overlaid with the encapsulating elastomer layer 3003.The slats 3004 may be made of a relatively rigid material or materialsas compared to the soft actuator body 3001, such as plastics, metals,ceramics, or stiffer elastomers.

FIG. 30C depicts the side of the soft actuator body 3001 having anencapsulating elastomer layer 3003, and FIG. 30D is a cross-sectionalview of the actuator depicted in FIG. 30C, showing the location of therigid slats 3004. FIG. 30E is an exploded view showing the rigid slats3004 between the strain limiting layer 3002 and the encapsulatingelastomer layer 3003.

FIG. 30F depicts an example of a soft actuator body 3001 having anencapsulating elastomer layer 3003, and furthermore having overmoldedrigid or elastomeric structures 3007 for reinforcing the accordiontroughs 3006 of the soft actuator bladder. The structures 3007 serve tominimize or reduce strain at the accordion troughs 3006. The pressure ofinflation of the soft actuator body 3001 may cause the troughs 3006 ofan accordion-shaped soft actuator to strain. This generates points ofstress concentration in the troughs 3006 which at elevated pressure canlead to the failure of the actuator. Nonetheless, elevating theinflation pressure of an actuator is desirable since this increases theforce that can be delivered by the actuator when it is used as part of agripper or the rigidity of the actuator when it is used as a structuralelement in an application. As a result it is desirable to reinforcethese troughs with rigid materials (e.g. plastics, metals, ceramics, orstiffer elastomers) in order to minimize the straining of the actuatorat these points when it is operated at elevated pressures.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralelements or steps, unless such exclusion is explicitly recited.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features.

While the present invention has been disclosed with reference to certainembodiments, numerous modifications, alterations and changes to thedescribed embodiments are possible without departing from the sphere andscope of the present invention, as defined in the appended claim(s).Accordingly, it is intended that the present invention not be limited tothe described embodiments, but that it has the full scope defined by thelanguage of the following claims, and equivalents thereof.

The invention claimed is:
 1. A soft robotic hub assembly comprising: amaster side assembly to be coupled to a mechanical robotic component; atool side assembly configured to be releasably coupled to the masterside assembly; and two or more soft actuators in at least two differentsizes coupled to the tool side assembly, the two or more soft actuatorsconfigured to transition from an unactuated configuration to an actuatedconfiguration independently of one another upon application of aninflating fluid to the soft actuator.
 2. The hub assembly of claim 1,further comprising an interface configured to releaseably couple themaster side assembly to the tool side assembly, wherein the interfaceprovides a seal for an inflation line connection that is configured toinflate the two or more soft actuators.
 3. The hub assembly of claim 2,wherein the interface comprises a series of pegs and slots, the pegsbeing configured to rotatably lock into the slots.
 4. The hub assemblyof claim 2, wherein the interface comprises a geometric recess and acorresponding geometric stepped portion configured to interlock.
 5. Thehub assembly of claim 2, wherein the interface comprises one or moreelectrostatic adhesion pads.
 6. The hub assembly of claim 1, wherein thetool side assembly is a first tool side assembly and the two or moresoft actuators are a first set of two or more soft actuators, furthercomprising: a second tool side assembly coupled to a second set of oneor more soft actuators, the second set of one or more soft actuatorsbeing deployed in a different configuration from the first set of two ormore soft actuators, wherein the first tool side assembly is configuredto be replaceable with the second tool side assembly.
 7. The hubassembly of claim 1, wherein the tool side assembly comprises one ormore electrical signal lines configured to be in electricalcommunication with one or more electrical signal lines in the masterside assembly when the tool side assembly and the master side assemblyare coupled together.
 8. The hub assembly of claim 1, wherein the hubassembly is configured to adjust an angle of the actuators.
 9. The hubassembly of claim 2, wherein the interface comprises a magneticinterface.